11279613
Description
Mind Map by Mikko Holden, updated more than 1 year ago
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Created by Mikko Holden
about 7 years ago
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Biology Y9 Topic 3: The Nervous System
- How it works
- Sensory receptor detects a
stimulous
- Information sent as an electrical impulse
along neurones
- Neurones are found in nerves
- The Impulse travels down neurones until it
reaches the CNS
- Made up of the Brain and spinal cord
- The brain sends the correct responses down
Motor Neurones to the rest of the body
- These carry the impulses that make the
effectors do the right things
- The effectors are either
muscles or glands
- Muscles respond by
contracting
- Glands respond by
releasing (secreting)
chemical substances
- Can be summed up as: Stimulus - receptor -
coordinator (CNS) - effector
- Muscles respond by
contracting
- The effectors are either
muscles or glands
- These carry the impulses that make the
effectors do the right things
- The brain sends the correct responses down
Motor Neurones to the rest of the body
- The neurones that carry the impulse to the
CNS are called sensory neurones
- Made up of the Brain and spinal cord
- Neurones are found in nerves
- Information sent as an electrical impulse
along neurones
- Sensory receptor detects a
stimulous
- Reflexes
- What are they for?
- Help you avoid
danger or harm
- Automatic and rapid
- Don't involve the
conscious part of the
brain
- Automatic and rapid
- takes care of Basic
body functions
- I.E. Breathing and moving food
through digestive system
- I.E. Breathing and moving food
through digestive system
- Help you avoid
danger or harm
- How do they work?
- Sensory Neurones are
connected to motor neurones
by relay neurones
- Electrical impulses are
sent along the
neurones until they reach the effector
- This is the reflex arc (brief)
- This is the reflex arc (brief)
- Sensory Neurones are
connected to motor neurones
by relay neurones
- What are they for?
- How synapses work
- Neurones aren't joined directly
- The junctions in between are
called synapses
- The junctions in between are
called synapses
- Electrical impulses travel across slower
than in the neurones, but the diffusion is
needed to get the impulse to the brain
- Neurones aren't joined directly
- Reflex arc in detail
- When you touch the object, a receptor in your skin is
stimuated. An elecrtical impulse from a receptor is
passed along a sensory neurone to the CNS - in this
case, the spinal cord
- When an impulse from the sensory Neurone arrives
at a synapse with a relay neurone, a chemical is
released. The chemical diffuses across the synapse
to the relay neurone, where it sets off a new
impulse that travels along the relay neurone
- When the impulse reaches the synapse between the relay neurone and a motor neurone returning to
the arm, another chemical is released. Again, the chemical diffuses across the synapse and starts
another impulse travelling down the motor neurone to the effector
- When the impulse reaches the effector organ, it is stimulated to respond. In this
example, the impulse arrives in the muscles, causing them to contract. This action
moves the hand rapidly away from the source of pain. If the effector organ is a gland, it
will respond by releasing chemical substances
- The reflex pathway is not very different from a normal conscious action. However, in a reflex
action the coordinator is a relay neurone either in the spinal cord or an unconscious part of
the brain. The whole reflex is very fast
- An impulse also travels up your spinal cord to the conscious part of your brain. You know about
the reflex action, but only after it has happened
- An impulse also travels up your spinal cord to the conscious part of your brain. You know about
the reflex action, but only after it has happened
- The reflex pathway is not very different from a normal conscious action. However, in a reflex
action the coordinator is a relay neurone either in the spinal cord or an unconscious part of
the brain. The whole reflex is very fast
- When the impulse reaches the effector organ, it is stimulated to respond. In this
example, the impulse arrives in the muscles, causing them to contract. This action
moves the hand rapidly away from the source of pain. If the effector organ is a gland, it
will respond by releasing chemical substances
- When the impulse reaches the synapse between the relay neurone and a motor neurone returning to
the arm, another chemical is released. Again, the chemical diffuses across the synapse and starts
another impulse travelling down the motor neurone to the effector
- When an impulse from the sensory Neurone arrives
at a synapse with a relay neurone, a chemical is
released. The chemical diffuses across the synapse
to the relay neurone, where it sets off a new
impulse that travels along the relay neurone
- When you touch the object, a receptor in your skin is
stimuated. An elecrtical impulse from a receptor is
passed along a sensory neurone to the CNS - in this
case, the spinal cord
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